In a photovoltaic system, a photovoltaic generator, formed from one or more photovoltaic modules, provides electrical energy by means of photovoltaic conversion. In order to ensure correct operation, it is necessary to monitor photovoltaic systems, in order to identify the occurrence of events that adversely affect correct operation of the device.
By way of example, events that adversely affect device operation may include theft of one or more components of a photovoltaic system, destruction of one or more components of a photovoltaic system, change in the conductivity of one or more electrical connections of a photovoltaic system (for example contact aging and/or a contact fault), deterioration of the efficiency of one or more photovoltaic modules (degradation), installation faults, for example faulty connection of one or more components during the installation of a photovoltaic system, and/or shadowing, for example shadowing of one or more photovoltaic modules of a photovoltaic system.
The above list of events that can adversely affect correct operation of a photovoltaic system does not claim to be complete, and in fact represents a choice of examples of events which can adversely affect correct operation of a photovoltaic system.
For example, high electric currents can occur during operation of the photovoltaic systems which, in some circumstances, can lead to considerable power losses by interacting with defective and/or damaged components. This relates in particular to contact resistances of contacts of connecting points of modules to one another and electrical line connections. Contact faults are evident, inter alia, by an increase in the contact resistance of the relevant electrical connection.
DE 10 2006 052 295 B3 describes a method and a circuit arrangement for monitoring a photovoltaic generator, specifying a fundamental principle for generator diagnosis with signal input and measurement between a photovoltaic generator and an inverter.
The known method is sensitive to incoupled disturbing signals, which can negatively influence the accuracy of required measurements. Interference such as this can be incoupled into the photovoltaic system from external components—which are not functionally related to the photovoltaic system—for example a source of electromagnetic radiation, or may be caused by components of the photovoltaic system itself, for example an inverter.